Combination of Modified P&O with Power Management Circuit to Exploit Reliable Power from Autonomous PV-Battery Systems

Abstract

Energy demand and conservation are two main concerns in distributed generation systems. Recently, lighting loads play a crucial role in these concerns. Nowadays, DC-fed LED lighting provides better solution. The conventional grid needs rectifier to provide DC results at high cost with low efficiency. Hence, a reliable autonomous PV-battery (APVB) system-fed LED load employing power management circuit (PMC) with maximum power point tracking (MPPT) has been presented to overcome these concerns. The undesirable oscillations at MPP associated with conventional perturb and observe algorithm are highly reduced by implementing variable step size-modified P&O algorithm. PMC includes non-isolated bidirectional converter as a charge controller which determines the battery charging and discharging mode depending upon state of charge, solar/converter output power and battery power with regulated DC bus voltage of 36 V. Performance has been analyzed with three MPPT and PMC through simulation. Moreover, to validate the effectiveness of the proposed approach, incremental conductance control is also employed and compared with results. In addition, the same was also tested with experimental setup by using developed prototype model with DSPIC30F2010 controller. Experimental results illustrate that the proposed system yields desired output voltage with superior performance via simplified control algorithm. Results proven that APVB provides stable and balanced power for any desired loads.